For a variety of applications, it is necessary to convert conventional interlaced video signal frames into a progressive scan format. For example, it may be necessary to convert an interlaced signal received over the air into a progressive scan format for display on a digital video monitor.
A number of de-interlacing techniques have been proposed. In one technique, motion detection is applied at the point where interpolation is occurring. If there is no motion, a “weave” approach is applied in which the pixel value to be generated is taken from the corresponding pixel in the preceding field. If there is motion at the current point, a “bob” approach is applied in which the pixel value to be generated by interpolation is obtained by interpolating the neighboring pixels from the lines (in the current field) above and below the pixel to be generated.
In another proposed technique, the pixel value to be generated is obtained as a weighted average of the pixel values that would be obtained by the “bob” and “weave” approaches, and the weights applied to the bob and weave pixel values vary depending on the degree of motion.
The above techniques may result in less than satisfactory image quality since combing artifacts, degradation of diagonal edges and “ghosts” may be produced by these techniques.